1. Field of the Invention
The present invention relates to a fuel tank for storing fuel.
2. Related Background Art
If there is a space above the fuel level in the fuel tank, the fuel will be evaporated and this evaporated fuel could be emitted to the atmosphere. For example, Japanese Laid-Open Patent Application No. H8-170568 discloses a fuel tank constructed in such structure that a fuel storage chamber for storing the fuel is made of an extensible envelope film and that the envelope film expands and contracts according to the amount of the fuel in the fuel storage chamber, thereby preventing the evaporated fuel from appearing above the fuel level in the fuel storage chamber. Specifically, the above envelope film is composed of an upper wall, a lower wall, and a side wall of a bellows shape connecting these upper wall and lower wall to each other, and the lower wall of the envelope film is attached to a flat bottom wall of a housing. The upper wall of the envelope film moves up and down in the housing, depending upon the fuel amount in the fuel storage chamber, and the side wall expands and contracts with the up and down motion of the upper wall. The capacity of the fuel storage chamber thus increases and decreases with the upper and down motion of the upper wall and the expansion and contraction of the side wall of the envelope film.